Hot-air furnace



` jan, 27, 1925.

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A. .lcaHNsoNv HOT AIR FURNACE me@ Jan. '25, 1924 2 Sheets-Sheet 2 through the stack.

not `only retard Patented Jan. 27, 1925.

UNITED STATES .ALFRED JGHNSON,

0ll SPOKANE, WASHINGTON.

HOT-AIR FURNACE.

Application filed .January 25, 1924.

To alt Iwhom t may concern.' v

e it known that l, ALFRED JOHNSON, a citizen of the United States, residing at Spokane, in the county of Spokane and 5 State of llashington, have invented new and 'b 'useful Improvements in Hot-Air Furnaces,

of which the following is a specification.

This invention relates to improvements in hot air furnaces for heating purposes.

lilly improved furnace includes an outer y shell or casing having a cold air intake and a hot air outlet with a fire box disposed in said casing, as is usual. lnjthis class of furnaces, a flue is employed not only to convey the products of combustion to the'stack, but

also to act as a heat radiator to heat the air in said casing. The function of heating thisair has heretofore been very imperfectly performed and has resulted in a loss of a material amount .of heat units escaping Now it is a primary object of this invention to improve the heat radiating flue with a view of radiating` substantially all the `heat units in the casing, and to this end, my invention, while residing in the` aforesaid combination, has to .do more particularly with an improved form of flue.

ln accordance with my invention, the improved flue is arranged and constructedl to the j aassage of the products of combustion toward the stack, as regards the speed .of flow, but also, and as a result of such retardation, to more completely radiate all the heat from said flue to the air inside of said casing.

A further feature consists ina disposition of the flue in such a manner that -it will radiate heat not only to theupper air areas hut to all vthe air `areas substantially throughout the height of said casing. y

A further feature consists in disposing and arranging said flue in such 4a manner that in addition to radiating` heat substantially l thrrniv'hout the height `ofsaid casing, itwill v also radiate heat substantially throughout the horizontal breadth of `said casing.

A primary feature of novelty `consists, in a flue for performing the functions vset forthV and which is a continuous flue, affording the products .of combustion a single and circuitous path of flow, certain .lengths of travel being constructed to retard, and certain lengths to facilitate the flow, these rctarding and facilitating lengths .being pref` enably alternately arranged Serial No. 688,454.

My invention has other features which will be more fully described in connection with the accompanying drawings and which will be more particularly pointed out in and y the appended claims.

F ig. l, is a vertical longitudinal sectional view at line l`l of Fig-ure 2.

l ig. 2, is a sectional view at line 2 2 of F ig.

Fig. 3, is a sectional view at line 3-3 of Fig. 2, with the tire box in elevation.

'.ike characters of reference designate similar parts throughout the different figures of the drawings. i

As shown, l, 2, 3 and 4, designate the front, rear and side walls of the outer shell or casing of my improved hot air furnace. The structure of the shell may be of brick, sheet iron or anyV desired type, this being immaterial to my invention. In the lower portion of wall 2, is a cold air inlet 5, and in the top `6, is a hot air outlet 7, which is shown provided with a pipe 8, adapted to convey the hot air to the room to be heated. It will be obvious to anyone familiar with furnaces that by providing pipe 8, with the usual and well known cold air return. the device of my invention would function as a pipeless furnace as well as a pipe furnace.

A fire box 9, is shown disposed in the casing and is very generally illustrated as the particular type of lire box is not important.. However, in this form, it will be seen that the fire box extends longitudinally in the casing and its rear end is suitably supported at 10, the front end being supported by the front wall l. A grate ll divides the fire box into upper combustion and lower ash chambers l2 and 13, respectively. A door lll, affords access to the chamber 1Q, and a door l5, likewise affords access to the ash chamber 13.

Reference will next be made to the improved heat radiating flue, which in combination with the foregoing, constitutes my invention.

My improved flue has an intake end or section `16, which is connected in communication with the fire box at l?, preferably near the rear end thereof. This flue has an outlet end or section 18, which extends through the casing and is` adapted for connection with a stack, not shown. The flue has an intermediate heat radiating section which not only extends substantially 2. c c Y Y 1,524,253

throughout the height but also substantially lower bights of the coils, and thereb the throughout the longitudinal area of the cas- `coils themselves, and it will be no that ing. Thus, it will be seen that by obtaining the coils are of such size and are supported Ythe widest possible distribution of the radi in such a manner as to be free from contact ating area, and reducing the interior of the with the fire box, whereby all the periph- 70 casing, substantially all of the air in the eries of the coils will thereby present radiatcasing is bound to come into eilicient heating surfaces to the air.

ing contact with the radiating section of the In order to deflect the air against the coils, flue as well as with the re box. Further, I I provide dellectors 32 and 33, which exniake the radiating` section of the flue of a tend from the walls of the casing toward 'l5 material of great heat conducting propern and preferably against the coils.

ties', such as thin sheet iron, whereby the It is believed that my invention will be greatest possible extent of heat 'radiation fully understood from the foregoing demay be obtained. Y Y scription, and while I have shown and den the specific form shown, I elevate the scribed one specific form of my invention, I B fire box 'to a relatively high position in the do not wish to be limited thereto except for casing, and I form the intermediate flue seosuch limit-ations as the claims may import. tion into a spiral coil of pipe'which sur- I claim rounds the re box. The convolutions are l. In a hot air furnace, an outer casing indicated at 19, 2O and 2l. It will be noted provided with a cold air inlet near the bot- 85 that the lower bights 22, 23 Vand 24, of the tom thereof and a hot air outlet near the coils,'have extensions 25, 26`and 27, which top thereof, a horizontal fire box di din project outwardly through 'the casing wall said casing, and aheat radiating ue hav 4l, and which are provided with closures 28, ing an intake end communicating with said 29 and 30. Thus it will be seen that these tir-e box and an intermediate radiating sec- 90 closures can be removed to permit the coils tion extending substantially throughout the to'be cleaned when they contain dust. height of said casing above and below the Now a special feature of novelty resides tire box and longitudinally in said casing to in a line, as described, which is continuous, radiate heat substantially throu hout the thereby providing a single circuitous path vertical and longitudinal areas o said cas- 05 for the products of combustion through ing, and said flue having an outlet section which all of the latter must pass before enextending outwardly through said casing tering the stack. By means of a continuousI and toward the stack.

fine` I obtain such a prolonged path of 2. In a hot air furnace, a casing having travel for the products of combustion, that a cold air intake and a hot air outlet, a o

I obtain practically all of the heat units horizontal fire box displosed in said casing,

therefrom.v v In actual practice, I have and a continuous flue avin one end confound that I can hold my hand against the nected with said fire box an the other end outlet section 18, when 'the furnace 1s in full extending through said casing, said Hue havoperation, thus proving that the radiating ing a thin heat radiating intermediate seclos section coils fully radiate all the heat to tion disposed in vertical convolutions about t Hthe air in the casing. It will be noted that said fire box, and means for deflecting the vwhen'the products of combustion are travyentering cold air toward said convolutions.

crsing a downward course through one of 3. In a hot air furnace, a casing having the downward lengths of the coils, there will a cold air intake and a hot air outlet, a subbe a resultant retardation of flow, and ythis stantially horizontally disposed. fire box in `retardation, in combination with the prosaid casing, and a continuous flue connected longed travel and the thin walls of the coils, with said fire box and having an end extendiesults in the complete and efficient radiaing through said casing, said flue havin tion intothe casing. an intermediate section spirally convolute Now in addition to the foregoing, it will in vertically disposed coils about said be lclear that the coils, which extend box and the coils extending longitudinally throughout the height of the casing and also thereof.

substantially throughout lthe longitudinal 4. In a hot air furnace, a casing having areas thereof, present heat radiating areas a cold air intake and a hot air outlet, a 1z0 to the incoming cold air at all elevations horizontal fire box in said casing, a conwithin the casin Thus, the cold air is, tinuous ilue having one end connected with or has heat applied thereto, from its ensaid lire box and the other end extending trance to its exit from the casing. through said casing, said flue havin an in- It will be noted that the casing is protermediate section coiled about said lire box, portioned so that the fire box and the coils the lower bights of each coil having a cleansubstantially ll the interior of said casing ing section extending outwardl through so that the air is forced to come into contact said casing and provided with c osures. 4 and be heated by the fire box and coils. 5, In a hot air furnace, a casing having I `provide supports 31, for supporting the' a cold air inlet and a hot air outlet, a hori- 130 Zonta] fire box disposed in said easing substantially mid-Way of the `height thereof7 and av continuous Hue haw/ing one end Connected with the top of Said ie box and the remaining end extending through said carsing, said lHue having an intermediate heat radiating section coiled about said fire box in substantially vertically disposed convolutions, and means for supporting said convolutions free from Contact With the le 10 box.

kIn testimony that I claim the foregoing as my own, I hereby affix my slonature.

ALFRED JoINSoN. 

